<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title>一列布局</title>
    <style>
        body {
            margin: 0;
            padding: 0;
            font-size: 30px;
            font-weight: bold
        }

        div {
            text-align: center;
            line-height: 50px
        }

        .head, .main, .footer {
            width: 80%;
            margin: 0 auto
        }

        .head {
            height: 100px;
            background: #ccc
        }

        .main {
            height: 600px;
            background: #FCC
        }

        .footer {
            height: 50px;
            background: #9CF
        }
    </style>
</head>

<body>
<div class="head">head</div>
<div class="main">main</div>
<div class="footer">footer</div>
</body>
</html>
